Getting execution time related errors

While uploading imageI got error

[Mon Mar 12 08:08:49.806592 2018] [fcgid:warn] [pid 8212] [client 157.41.202.211:38340] mod_fcgid: stderr: PHP Warning:  file_get_contents(http://www.php.net/releases/index.php?serialize=1): failed to open stream: Connection timed out in /var/www/vhosts/xxxxxxx.com/httpdocs/inc/classes/BxDolAdminTools.php on line 559, referer: https://xxxxxx.com/administration/

[Mon Mar 12 08:12:43.720292 2018] [fcgid:warn] [pid 8053] [client 157.41.202.211:38504] mod_fcgid: stderr: PHP Fatal error:  Allowed memory size of 134217728 bytes exhausted (tried to allocate 4000 bytes) in /var/www/vhosts/xxxxxxx.com/httpdocs/plugins/intervention-image/Intervention/Image/Gd/Decoder.php on line 115, referer: https://xxxxxxx.com/m/store/browse/my/&bx_store_filter=add_product

While accessing host tools in admin, I got page error.

Came to know because of php max execution time. After changing to 120 from 30, host tools are accessible.

What is the default for execution time?

You need to discuss these with your hosting provider.  As for execution time, it depends on what you are doing.  I had an import script that needed a long execution time in order to complete the import.  However, it was on a dedicated server so it was no problem.  That is going to depend on how you are hosting your site.

Since you decreased your execution time, there was probably a script that was taking some time to execute.  By reducing to 30 you basically killed that script before it finished and thus the host tool page loaded.

First error. Looks like it couldn't fetch the PHP version URL. Dolphin shows in the Host Tools if the PHP version is up-to-date, although it's not always correct. Maybe the server was down, or it hit a timeout limit before it could finish. You wrote that max_execution_time was reduced from 120 to 30 - both of those are too low. max_execution_time needs to be 300 at minimum for Dolphin to work correctly.

Second error: PHP memory_limit was reached when Dolphin tried to process a photo upload. Try upping it to 256M and see if that helps.

Thank you @geek and @nathan.

So the errors are due to the image I tried to upload (above 2mb) and also php max_execution _time is 30sec.

The errors are due to your host settings.  If you are on a shared hosting that severely limits these settings then there is nothing you can do but change hosting companies.  I stated to check with your hosting company. 

Yes. You should be able to up these in a php.ini or .user.ini file. Your control panel may also have a place to easily change them. If you need help making these changes or if they don't seem to be applying, then do what geek_girl said and contact your host's support.